This invention relates to a switch structure of a lamp unit such as a room lamp, which is mounted at a lamp-mounting window formed in an interior wall member (such as a roof trim) covering a vehicle body panel.
In one related structure, a lamp unit such as a room lamp is beforehand mounted on an interior wall member (such as a roof trim) to form a roof module, and this roof module is mounted on a vehicle body panel, thereby enhancing the efficiency of the lamp unit-mounting operation. JP-A-2002-79879 (Pages 15 to 17, FIGS. 19 to 22) discloses one example of such lamp unit-mounting structures as shown in FIG. 6.
In this lamp unit-mounting structure, a room lamp (lamp unit) 3 is mounted at a lamp-mounting window 2 formed in a roof trim (interior wall member) 1 covering a vehicle body panel (not shown).
The room lamp 3 includes a lamp function portion A having a switch unit 4, and a design portion B including a cover lens 8 having a switch knob 7 slidably retained thereon. The switch knob 7 has an engagement portion 17 engaged with a switch lever 5 of the switch unit 4. The cover lens 8 is mounted on the roof trim 1 from the inside of a car room,
Wires such as an FFC (flexible flat cable) 10 are connected to wire connection portions (not shown) of a switching circuit of the switch unit 4. The switch lever 5 for activating and deactivating the switching circuit capable of switching a bulb 11 of the lamp function portion A between the ON and OFF states is provided at the switch unit 4.
The switch knob 7 is beforehand slidably retained in a slide groove 13 formed in the cover lens 8. The cover lens 8 is mounted on the roof trim 1 from the inside of the car room to cover the lamp-mounting window 2, with retaining projections 14 engaged respectively in engagement holes 15 in the roof trim 1.
A pair of limitation projections 16 are formed on an inner surface the cover lens 8, and are disposed near to the slide groove 13, and these limitation projections 16 hold the switch unit 4 therebetween to limit or prevent the displacement of the cover lens 8 relative to the lamp function portion A in a direction of sliding of the switch knob 7.
The switch knob 7 has the engagement portion 17 in which a distal end portion of the switch lever 5 can be engaged. As shown in FIG. 7A, this engagement portion 17 is formed or defined by a pair of elastic arms 18 each having opposite end portions extending obliquely inwardly in a direction of the width of the slide groove 13. This engagement portion 17 serves as a retaining unit into which the distal end portion of the switch lever 5 can be inserted in the sliding direction.
Therefore, the distal end portion of the switch lever 5 can be inserted into the engagement portion 17 while elastically deforming the opposed elastic arms 18 in the sliding direction (see FIG. 7B). The distal end portion of the switch lever 5, thus received in the engagement portion 17, is retained by the elastic arms 18 against disengagement therefrom in the sliding direction.
When the room lamp 3 is to be mounted on the roof trim 1 to form a roof module, first, the lamp function portion A is mounted at th lamp-mounting window 2 in the roof trim 1, and then the cover lens 8 is attached to the room trim 1 to cover the lamp-mounting window 2, with the retaining projections 14 of the cover lens 8 engaged respectively in the engagement holes 15 in the room trim 1.
At this time, the distal end portion of the switch lever 5 is not engaged in the engagement portion 17 of the switch knob 7 as shown in FIG. 7A since the cover lens 8 is merely mounted relative to the lamp-mounting window 2. However, merely by sliding the switch knob 7 in a direction of an arrow in FIG. 7A after this mounting operation, the distal end portion of the switch lever 5 can be inserted into the engagement portion 17 as shown in FIG. 7B.
Therefore, at the time of mounting the cover lens 8 relative to the lamp-mounting window 2, there is no need to adjust the position of the switch knob 7 so that the distal end portion of the switch lever 5 can be positively inserted into the engagement portion 17. Merely by operating the switch knob 7, retained on the cover lens 8, after the cover lens 8 is fixed to the roof trim 1 to cover the lamp-mounting window 2, the retaining unit, provided at the engagement portion 17 of the switch knob 7, allows the switch lever 5 to be inserted into this engagement portion in the sliding direction, and therefore the switch lever 5 is positively engaged in the engagement portion 17 of the switch knob 7.
Therefore, the operator, engaged in this mounting operation, is not required to effect any positioning operation when he fixes the cover lens 8 to the roof trim 1, and ther fore the mounting operation can be carried out asily. And besides, the switch lever 5 can be easily and positively brought into engagement with the engagement portion 17 of the switch knob 7, and therefore a defective connection during the assembling operation is prevented, so that the quality is enhanced.
In the above related lamp unit-mounting structure, however, the retaining unit, provided at the engagement portion 17 of the switch knob 7, is formed by the pair of elastic arms 18 which allow the switch lever 5 to be inserted into the engagement portion only in the sliding direction, and these elastic arms 18 can not be elastically deformed in the direction of mounting of the cover lens 8.
Therefore, when the cover lens 8 is moved so as to be mounted at the lamp-mounting window 2, with the distal end portion of the switch lever 5 so disposed as to abut against the elastic arms 18 of switch knob 7 in the mounting direction, the distal end of the switch lever 5 imparts an impact to upper edges of the elastic arms 18, which results in a possibility that the cover lens 8 fails to be properly mounted, thus inviting the defective connection, and therefore there has been encountered a problem that the efficiency of the mounting operation for the room lamp 3 is not enhanced.